Currently, there are generally two kinds of seat recliner. One kind of seat recliner is of a leaf-spring adjusting mechanism based on a principle of ratchet mechanism; and the other kind of seat recliner is of a gear adjusting mechanism based on a principle of planetary gear transmission.
Referring to FIGS. 1 to 3, FIG. 1 is an external structural diagram of a seat in the prior art; FIG. 2 is an assembly exploded view of a seat recliner in an embodiment in the prior art; and FIG. 3 is a structural simplified diagram of a gear transmission mechanism in the seat recliner as shown in FIG. 2.
A conventional seat recliner 00 is mounted between a seat back and a seat base, and generally implemented through a planetary gear transmission, as shown in FIG. 1.
As shown in FIGS. 2 and 3, the conventional seat recliner 00 includes an inner toothed plate 01 having an inner toothed rim, an outer toothed plate 02 having an outer toothed rim, an eccentric wheel 03, a wedge block 04, and a drive cam 05. Specifically, the inner toothed plate 01 is adapted to be fixedly connected with the seat back, and the central portion of the inner toothed plate 01 is provided with a shaft shoulder 011. The outer toothed plate 02 is adapted to be fixedly connected with the seat base, and the central portion of the outer toothed plate 02 is provided with a central hole 021. The outer toothed rim is meshed with the inner toothed rim, and a radial eccentric area is formed between the shaft shoulder 011 and the central hole 021. The eccentric wheel 03 is placed in the radial eccentric area. The eccentric wheel 03, the inner toothed plate 01 and the outer toothed plate 02 constitute a planetary gear transmission mechanism with few tooth difference. The wedge block 04 is placed in the radial eccentric area, and under a circumferential force applied by an elastic member, the eccentric wheel 03 and the wedge block 04 eliminate gaps between the eccentric wheel 03 and the central hole 021 of the outer toothed plate 02 and between the meshed teeth. The drive cam 05 drives the eccentric wheel 03 or the wedge block 04, so as to enable a relative rotation between the inner toothed plate 01 and the outer toothed plate 02 by an angle.
When the drive cam 05 drives the eccentric wheel 03 or the wedge block 04 to rotate, the eccentric wheel 03 and the central hole 021 of the outer toothed wheel 02, the eccentric wheel 03 and the shaft shoulder 011 of the inner toothed plate 01, the wedge block 04 and the central hole 021 of the outer toothed wheel 02, and the wedge block 04 and the shaft shoulder 011 of the inner toothed plate 01 constitute four friction pairs each undergoing three stages of oil lubrication, boundary friction and dry friction.
The oil lubrication means the friction with lubricating oil between two friction surfaces. The boundary friction means that, there is lubricating oil between two friction surfaces, and an extremely thin boundary oil film is formed on the metal surface due to the absorption between the lubricating oil and the metal surface and has the thickness of less than 1 μm, which is not sufficient to separate two metal surfaces, so that the microcosmic peaks of the two metal surfaces will rub against each other while moving relative to each other. The dry friction means the friction without lubricating oil.
At the beginning stage, each of the above friction pairs remains in oil lubrication and boundary friction. With the increasing use, the lubricating oil between two components forming a friction pair are rolled to two ends of the friction surfaces, so that the friction between the friction pair will turn into the dry friction. Then, the wear between the two components forming the friction pair is aggravated. After a certain degree of wear, a shaking gap will be formed between the seat recliner 00 and the seat, so that noise, shaking and so on may exist in operation, and therefore the comfort of the seat may be affected.
With the development of auto industry, higher and higher requirement are imposed on the service life and comfort of the seat. However, the service life and comfort of the seat are greatly influenced by the seat recliner 00. Thus, the conventional seat recliner 00 fails to meet the requirement of users.
Therefore, a technical problem to be solved presently by the person skilled in the art is to design a seat recliner which may reduce the wear of its inner friction pairs and prolong its service life.